The major goal in this laboratory will be to synthesize gram quantities of biologically active peptides which are needed for biochemical, pharmacological, biological and biophysical studies in this Program Project. Facilities for synthesis, purification and analysis will be available. The specific aims of The Core Facility are: 1. To prepare 1-2 g quantities of DPDPE and [p-ClPhe4]DPDPE in high purity for a variety of biochemical, pharmacological, and biophysical studies, as well as studies of bioavailability, biodegredation and toxicity. 2. To prepare 1 g of [Cys5, Cys11]Dynorphin A1-11-NH2 for a wide variety of biological studies as in 1. 3. To prepare 1 g of CTAP, a potent and highly eta opioid receptor selective peptide, to assess its antagonist effect as an opioid and to examine its biostability. 4. To prepare whether peptide ligands as needed in the various projects of the Program Project. 5. To prepare quantities of the new compounds which cross the blood brain barrier more effectively for extensive biological and biodistribution studies.